The present disclosure relates to a method of making a supported catalyst and the use of the supported catalyst for reforming of hydrocarbons with steam to produce hydrogen and/or synthesis gas.
Steam-hydrocarbon reforming, also called steam-methane reforming, or SMR, is routinely used by the chemical processing industry to produce hydrogen or synthesis gas. Synthesis gas or syngas is a mixture comprising hydrogen and carbon monoxide. The reforming process is generally carried out at high temperature and pressure to facilitate reaction between steam and methane in the presence of a nickel catalyst supported on alumina, calcium aluminate, magnesium aluminate or any other suitable material. It is a common practice to promote nickel catalyst with potassium to avoid carbon formation in the top portion of the reforming tubes when processing a feedstock containing hydrocarbons having 2 or more carbon atoms. Often times, reformer feed containing minor amounts of C2+ hydrocarbons present in natural gas or heavier hydrocarbon feedstock such as propane, butane and naphtha are pretreated in a prereformer in the presence of nickel catalyst (called prereforming catalyst) to convert the C2+ hydrocarbons to methane prior to steam reforming them to produce hydrogen or synthesis gas.
Nickel-based reforming catalyst typically contains 10 to 25 weight percent nickel in the form of nickel oxide irrespective of potassium promotion. Nickel-based reforming catalysts are supported on refractory alumina, calcium aluminate, magnesium aluminate or any other suitable support material. The porosity of commercially available unpromoted or potassium- or lanthanum-promoted nickel catalyst supported on alumina or calcium aluminate or magnesium aluminate varies from 30 to 40%. The pore volume is less than 0.3 cc/g.
The nickel-based prereforming catalyst contains considerably higher amounts of nickel than reforming catalyst—the nickel content calculated as nickel oxide can vary from 50 to 60 weight %. High nickel content is generally used in prereforming catalysts to provide high activity at low temperatures. The porosity of prereforming catalyst is considerably higher than that of a reforming catalyst—the porosity of a commercially available prereforming catalyst is about 50% compared to 30 to 40% for reforming catalyst. The pore volume of prereforming catalyst is similar to that of reforming catalysts, i.e. less than 0.30 cc/g.
Industry desires steam-hydrocarbon reforming catalysts having high activity for use in prereformers and primary reformers.
Industry desires steam-hydrocarbon reforming catalysts that suppress carbon formation, especially when processing feedstock having C2+ hydrocarbons.
Industry desires steam-hydrocarbon reforming catalysts that do not release corrosive leachates and are compatible with downstream equipment.